What would be an appropriate modern engine for a Dumas Thunderbird? I have an LA-25, an LA-46, a possible FP 25 and a Magmum GP 42, and a Magnum XL 32 and a McCoy 35.  What would you recommend, given that list.  The Dumas plans call for a Veco 35.

  The Thunderbird is a health sized model. Stick with a .40 or larger, especially if using kit wood.
  Type at you later,
   Dan McEntee

I am always surprised that no one ever talks about the Evolution 36 NT. It is a BB engine and out spins an OS 46 LA. It is also a lighter engine. I have one on a Brodak P40 and it runs as well as any OS engine I have. (And I do like my OS's!)

Colin,

One reason is likely that in my experience, the Evo .36NT-CL was an inconsistent engine. I have three. At our field, I have seen one that I thought was a good runner. It may not have been a coincidence that it was in a fairly small plane? An early Thunderbird, mounted upright. I'm not sure what, if anything, was done inside it. If you are having success with yours, why not share the full list of details?

The .36 is a whole different animal than the control line .60, which will really run well. I have one in a T-Rex.

Dave

Thanks Dave.

I don't experience the inconsistency on my engine run. The EVO 36 NT on my profile P40 is stock and the CL version. No idea if an upright (or down) mounted engine will operate differently.

I am running it with the smallest venturi (it came w/ 3 different sizes). And no mods to the 'set-right' needle. The set right needle only allows for one complete turn. At minimum it is a nice wet 2-stroke (around 10,000 rpm w/ a 11-4 wood BY&O prop and 5% nitro fuel). At full open (one complete turn) around 13,700 rpm w/ same prop. Have also been running Brodak 5% nitro fuel (50/50 oil).

It is really too much engine for the Brodak P40 ARF, but I run it about 45 deg open from minimum setting, probably around 11,000 rpm. Maybe I just have a good engine, but it is easy to start and runs rock solid for the entire flight.

I have heard others mention to use the smallest venturi. And that the larger venturis are more difficult to tune. The stock setup w/ smallest venturi has worked well for me. I also use the tube muffler. It also came w/ a tongue muffler. I am also running it w/ the EVO stock glow plug it came with.

One other thing. It likes to be really wet to start. I choke-prime maybe 10 or so flips. Then usually starts w/ 2-3 flips. 

Colin,

Thanks for sharing your setup information. You must have gotten a good one and matched it up just right. Glad they are working for someone out there....

Dave

"The CS .46 would pull it with authority , and save nose weight ."

Yeah, I have the CS 46 which we (my brother and I haven't tried).  If it runs like a Magnum 46XL, It could overpower the plane.